Currently deployed wireless LANs (Local Area Networks) are generally based on the IEEE (Institute of Electrical and Electronic Engineers) 802.11 MAC (Media-specific Access Control) protocol. Generally, using the 802.11 MAC each transmitter and receiver uses one or two omni-directional antennas for data handling, such as data transmission and reception. For a receiver the general purpose of the two omni-directional antennas is to choose one antenna from the two available antennas that has the best signal quality (e.g., as measured using signal-to-noise ratio) so that the signal can obtain a diversity gain and fading can be mitigated. However, when using an omni-directional antenna data is transmitted to all directions and is received from all directions. For this reason nodes close to either the transmitter or the receiver should preferably remain silent so that the close-in nodes do not interfere with communications between either the transmitter or the receiver. Such an arrangement keeping close-in antennas silent is known as a “clearing the floor” or CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) strategy. A CSMA/CA strategy assures a certain level of collision free communications. However, as a side effect, a CSMA/CA strategy limits the capacity of a network by forcing nodes near either the transmitter or the receiver (i.e., close-in nodes) to remain silent.
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